Application of nanoparticles for materials recognition using peptide phage display technique - Part II: Magnetic bio-panning using Fe₃O₄ nanoparticles

The magnetism of Fe₃O₄ nanoparticles was applied to magnetic bio-panning process for finding specific sequences against Fe₃O₄ crystal phase. Vibrating sample magnetometer (VSM) measurement showed that the coercivity of 30 Oe and the saturation magnetization of 55 emu/g were sufficient in controlling particle movement and magnetizing particles in the media, respectively. This ferrimagnetism of nanoparticles practically enhanced panning efficiency by exaggerating centrifuge step and preventing particle loss. Sequencing results showed that histidine which was commonly found in peptide sequences played an important role in the binding onto Fe₃O₄ nanoparticle surface. However, various possible motifs were also observed from several neighboring amino acids of histidine.